Phyllis Delma Dewar (March 5, 1916 – April 8, 1961), also known by her married name Phyllis Lowery, was a Canadian competition swimmer and freestyle specialist. At the 1936 Summer Olympics in Berlin, Germany, she was a member of the Canadian relay team that finished fourth in the women's 4×100-metre freestyle relay. In the 100-metre freestyle, she advanced to the semifinals of the event before being eliminated.